Method of forming a beaded transfixion wire

ABSTRACT

A method of forming a beaded transfixion wire for orthopedic uses. The beaded transfixion wire includes an elongated wire formed of an implant grade material. A bead is provided on the elongated wire intermediate the opposite ends thereof. The bead extends outwardly beyond the outer surface of the elongated wire and is integral therewith. 
     In forming the beaded transfixion wire the solid bar stock is rotatably fed past a cutting tool to turn down a portion of the bar stock to a selected daiameter to provide a first portion of an elongated wire. The first portion of the elongated wire is fed into a tube for stabilizing the first portion against any whipping motion. The solid bar stock is continued to be rotated past the cutting tool while at the same time a bead is profiled from the solid bar stock with the cutting tool. After the bead has been formed in the bar stock another portion of the bar stock is turned down to the selected diameter to provide a second portion of the elongated wire having the selected diameter.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of my application Ser. No. 07/288,426 pending, filedDec. 22, 1988, entitled "Beaded Transfixion Wire and Method of FormingSame".

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates, in general, to the method of formingbeaded transfixion wires or pins for orthopedic uses.

2. Information Disclosure Statement:

Heretofore, beaded transfixion wires or pins have been formed from twoparts, i.e., a wire and a bead. The prior art methods of forming thebeaded transfixion wire or pin included the steps of providing a hole inthe bead and fitting the bead on the wire by extending the wire throughthe hole. The next step was then to fix the bead onto the wire by silversoldering, welding, crimping or the like. The final steps were toprovide a drill point on one end of the beaded transfixion wire, andthen to finish the product by polishing same, as for example to smoothout the soldering or welded joint between the wire and the bead.

So-called Swiss-type for sliding-headstock machines are known in theprior art and some include a tube feeder, sliding-headstock, a guidebushing having a collet, a cutting tool, and a support which the end ofthe stock engages to eliminate deflection. Although such machines havebeen known in Europe for many years and the problems in manufacturingtransfixation wires or pins formed from two parts have also been knownfor a long time, due to the small diameter and length of such wires orpins, prior to the present invention no thought has been given toforming the wires or pins with the bead being integral with the wire orattempting to form same on such sliding-headstock machines. Thefollowing publications provide examples of such sliding-headstockmachines: Tool and Manufacturing Engineers Handbook (3rd Edition), pages5-121-5-127; Marubeni Citizen-Cincom Inc. brochure; Citizen Watch Co.,LTD. catalog No. 150E, 1986; Citizen Watch Co., LTD. catalog No. 121E,1985; Star Micronics Co., LTD. catalog RNC-16; Star Micronics Co., LTD.catalog KNC-16.20; and Star Micronics Co., LTD. catalog KNC-25/32.

Ilizarov et al U.S. Pat. No. 4,615,338 issued 10/7/86 shows one type ofautomatic compression-distraction apparatus with which the beadedtransfixion wire of the present invention may be used.

SUMMARY OF THE INVENTION

The present invention is directed towards providing an improved,efficient, and economical method of forming a beaded transfixion wire orpin for orthopedic uses.

One of the objects of the present invention is to provide a method forforming such a beaded transfixion wire or pin in which the bead isintegral with the elongated wire, i.e., the product of the presentinvention is formed from a single solid piece of material so that ratherthan being of two parts, as prior beaded transfixion wires or pins, thebead and elongated wire comprise a single unitary and solid piece.

A further object is to provide a method for forming such a beadedtransfixion wire which can be F.D.A. approved as opposed to some of theprevious beaded transfixion wires which were silver soldered.

A further object is to provide a method for forming a beaded transfixionwire or pin which is stronger than previous devices such as those inwhich the beads were pressed onto the elongated wire or were welded.

The beaded transfixion wire or pin formed by the method of the presentinvention includes an elongated wire formed of an implant grade materialand terminating in a first end and a second opposite end with saidelongated wire having an outer surface, a bead provided on saidelongated wire intermediate said first and second ends, and beadextending outwardly beyond said outer surface of said elongated wire andbeing integral with said elongated wire.

The method of the present invention includes the steps of (1) rotatablyfeeding solid bar stock at a selected advancement rate past a cuttingtool fixed in a first position to turn down a portion of said bar stockto a selected diameter to provide a first portion of said elongated wirehaving said selected diameter; (2) feeding said first portion of saidelongated wire into tube means for stabilizing said first portionagainst any whipping motion; (3) continuing to rotatably feed said solidbar stock past said cutting tool while at the same time profilling abead from said solid bar stock by moving said cutting tool outwardly andinwardly relative to the direction of travel of said bar stock; and (4)after said bead has been formed in said bar stock and with said cuttingtool positioned in said first position turning down another portion ofsaid bar stock to said selected diameter to provide a second portion ofsaid wire having said selected diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the beaded transfixion wire formedby the method of the present invention.

FIG. 2 is an enlarged sectional view taken as on the line II--II of FIG.1.

FIG. 3 is an enlarged fragmentary sectional view of the beadedtransfixion wire formed by the method of the present invention taken ason a plane through the longitudinal centerline thereof.

FIG. 4 is a perspective view showing one application of the beadedtransfixion wire formed by the method of the present invention.

FIG. 5 is a perspective view showing another application of the beadedtransfixion wire formed by the method of the present invention.

FIGS. 6-8 are diagrammatic views illustrating steps of the method of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIEMT

The beaded transfixion pin or wire 11 formed by the method of thepresent invention includes an elongated wire 13 formed of a suitableimplant grade material, as for example, titanium or stainless steel S.Elongated wire 13 terminates in a first end 15 and a second opposite end17, and has a outer surface 19. Beaded transfixion wire 11 also includesa bead 21 provided on elongated wire 13 intermediate first end 15 andsecond end 17. Bead 21 extends outwardly beyond outer surface 19 and isintegral with elongated wire 13. It should be pointed out that when bead21 is described herein as being "integral" with elongated wire 13 it isto be understood as meaning that the bead 21 is formed from the samesolid piece of material as elongated wire 13 to provide beadedtransfixion wire 11 as a single unitary and soldi piece. In other words,it is one single piece of materal as opposed to being formed of twoparts as with prior art pins which comprised a bead with a hole thereinthrough which the wire extends and with the bead being fixed onto thewire with solder, crimping or the like.

For purposes of clarity and understandeing the portion of elongated wire11 between bead 21 and first end 15 is herein designated as firstportion 23 and the portion of elongated wire 11 between bead 21 andsecond end 17 is herein desingated as second portion 25.

Elongated wire 13 is preferably circular in cross section with thediameter of the elongated wire being preferably 1.5 millimeters orapproximately of that diameter. Bead 21 is also preferably circular incross section with the diameter of the bead being preferably 4.5millimeters or approximately of that diameter, and preferably beingconcentric with respect to the longitudinal axis 27 of elongated wire13. Beaded transfixion wire 11 is of any suitable overall length, as forexample 155/8 inches (396.88 millimeters). Bead 21 is of any suitablelength, as for example 1/4 inch (6.35 millimeters) with the beadpreferably being closer to one end of the beaded transfixion wire thanthe other, as for example, first portion 23 being 91/4 inches (234.95millimeters) and second portion 25 being 61/8 inches (155.58millimeters). The reason for bead 21 being closer to second end 25 thanto first end 15 will be better understood in the description to followlater in the specification of the use of the beaded transfixion wire 11formed by the method of the present invention. Beaded transfixion wire11 is preferably provided with a suitable drill point 29 at first end 15for a purpose later to be described.

The beaded transfixion wires 11 formed by the method of the presentinvention are adapted for various orthopedic uses in the same manner asprevious beaded transfixion wires or pins have been used. See forexample, the various uses of pins in U.S. Pat. No. 4,615,338, and seeFIGS. 4 and 5 of the drawings herein. Thus, in FIG. 4 there is shownbeaded transfixion pins or wires 11 which are used in reducing fracturesin the bone B. The rings 31 are fastened together with rods 33 and eachof the beaded transfixion wires 11 are inserted into the bone B as bybeing drilled thereinto with a drill, not shown, which causes the drillpoint 29 to penetrate the bone until the bead 21 engages the bone tostop the penetration of the beaded transfixion wire 11 into the bone.The beaded transfixion wires 11 are then tensioned and secured to rings31 by gripping devices 35 well known to those skilled in the art, andthe fracture is then reduced by applying the proper compression in amanner well known to those skilled in the art. Also, in the case of thereduction of a bone fragment an additional beaded transfixion wire 11shown as at 11' may be provided and supported from one of the rings 31by suitable means as supports 37. The bone fragment F can then bemanupulated as desired to move the fragment into place. From theforegoing, it will be understood that bead 21 is preferably closer tosecond end 17 than to first end 15 to compensate for the thickness ofthe bone. Also, it will be understood that the flesh, skin, andremaining portions of the persons's body have been omitted for purposesof illustration.

In FIG. 5 is shown an example of bone elongation in which beadedtransfixion wires or pins are used. This is a process which wasdeveloped by Dr. Gavrill A. Ilizarov of the Soviet Union and furtherinformation regarding this type of procedure may be found in Gavrill etal U.S. Pat. No. 4,615,338. In FIG. 5 there is shown the bone after acorticotomy has been performed in which a section of the cortex of thebone has been removed exposing the medulla M. After as optimum time haselapsed the bone is then ready for the start of the lengthening process.Also, it will be noted that rods 33 are provided with adjustment means57 for use in the extension process.

The preferred method of the present invention for forming beadedtransfixion wires 11, in general comprises the steps of: (1) feedingsolid bar stock B of a suitable implant grade material, as titanium orstainless steel S, from a tube feeder 41 into a sliding head stockdevice 43 where the bar stock B is continuously rotated as indicated bythe arrow 45 and advanced longitudinally along a line of travel in thedirection indicated by the arrow 46; (2) after leaving sliding headstock device 43, feeding the rotating and advancing bar stock B througha guide bushing 49 and past a cutting tool 47 fixed in a first positionto turn down a portion of bar stock B to a selected diameter to providefirst portion 23 of elongated wire 13 having a selected diameter, as forexample, 1.5 millimeters; (3) feeding first portion 23 of elongated wire13 into a hollow tube 51 for stabilizing first portion 23 against anywhipping motion; (4) continuing to rotatably feed solid bar stock B pastcutting tool 47 while at the same time profiling a bead 21 from solidbar stock B by moving cutting tool 47 outwardly and inwardly relative tothe direction of travel 46 of bar stock B; and (5) after bead 21 hasbeen formed in bar stock B and with cutting tool 47 positioned in saidfirst position, turning down another portion of bar stock B to saidselected diameter to provide a second portion 25 of elongated wire 13having said selected diameter.

Except for tube 51, the above mentioned components, namely, tube feeder41, sliding-headstock device 43, cutting tool 47, and guide bushing 49are well known to those skilled in the art and being components of aso-called Swiss-type or sliding-headstock machine, the operation ofthese components, except for the forming of a beaded transfixion wire onsuch a machine and the feeding of the first portion of the elongatedwire into tube 51, is well known to those skilled in the art.

More specifically, from the tube feeder 41 the bar stock B is fed intothe sliding-headstock device 43 which has mechanisms therein, not shown,well known to those skilled in the art, which cause the bar stock B torotate about its longitudinal axis and at the same time thesliding-headstock slides to the right, as shown by the arrow 46 in FIG.6 to move the rotating bar stock B to the right therewith so that thebar stock advances past cutting tool 47 which is in a selected fixedfirst position to turn down a portion of bar stock B to provide a firstportion 23 of the elongated wire 13.

Between sliding-headstock device 43 and cutting tool 47 is preferablyprovided a stationary guide bushing housing 53 that houses guide bushing49 which permits bar stock B to turn and to advance yet holds the barstock at a place adjacent and upstream of cutting tool 47 rigidlyagainst movement out of the line of travel of the bar stock B in amanner well known to those skilled in the art.

The end 15 of first portion 23 is fed into tube 51 (see FIG. 6) which isfixedly supported by suitable means, such as welding or the like, on asliding tailstock support 54, which tailstock support is well known tothose skilled in the art.

As solid bar stock B is continued to be rotated and advanced pastcutting tool 47 a bead 21 is profiled, i.e., formed from the bar stockby moving the cutting tool outwardly and inwardly relative to thedirection of travel of the bar stock. This movement is carried out bysuitable means, not shown, but well known to those skilled in the artand may be done by computer control to cause the cutting tool to move atthe appropriate time and by an appropriate amount.

After bead 21 has been formed in bar stock B and with the cutting tool47 returned back to said first position, cutting tool 47 begins to turndown second portion 25 at the same selected diameter as said firstportion 23. At the same time the first portion 23 continues to be fedinto tube 51 until bead 21 abuts the end of the tube (see FIG. 7). Atthis time the first portion 23 is completely into tube 51 whichstabilizes the first portion against any whipping motion. Also, at thistime the sliding tailstock support 54 begins to move with the bead 21and first portion 23 as shown by the arrow 55, and continues suchmovement until the cutting tool 47 has completed the forming of secondportion 25. This movement is accomplished by suitable means, not shown,well known to those skilled in the art and preferably includes computercontrol means. After second portion 25 has been formed, the secondportion is detached form bar stock B by cutting the material withcutting tool 47 as by causing the cutting tool to be moved inwardely bysuitable means well known to those skilled in the art. FIG. 8 shows thevarious components just before this last mentioned detachment step isperformed.

It will be understood that in the heretofore described preferred methodin which the bead 21 abuts the end of the 51, the inside diameter oftube 51 is slightly greater than the outside diameter of first portion23 but is less than the diameter of bead 21 so that only first portion23 will move completely into tube 51 and will be stabilized against anywhipping motion. However, if desired, the inside diameter of tube 51 maybe slightly greater than the outside diameter of bead 21 in which casethe bead as well as first portion 23 and a part of second portion 25 maymove into tube 51, and tailstock support 54 may remain stationary withthe bead 21 stabilizing the beaded transfixion wire 11 against whippingmotion.

Finally, after beaded transfixion wire 11 has been parted from the barstock B, a drill point 29 is provided on first end by any suitable meansor method well known to those skilled in the art.

Although the present invention has been described and illustrated withrespect to a preferred embodiment and a preferred use therefor, it isnot to be so limited since modifications and changes can be made thereinwhich are within the full intended scope of the invention.

I claim:
 1. A method for forming a beaded transfixion wire fororthopedic uses comprising the steps of:(a) rotatably and longitudinallyfeeding solid bar stock along a line of travel at a selected advancementrate past a cutting tool fixed in a first position to turn down aportion of said bar stock to a selected diameter to provide a firstportion of an elongated wire having said selected diameter; (b) whilerotatably and longitudinally feeding said solid bar stock along saidline of travel past said cutting tool feeding said first portion of saidelongated wire into tube means for stabilizing said first portionagainst any whipping motion; (c) continuing to rotatably feed said solidbar stock past said cutting tool while at the same time profiling a beadfrom said solid bar stock by moving said cutting tool outwardly andinwardly relative to the direction of travel of said bar stock; and (d)after said bead has been formed in said bar stock and with said cuttingtool positioned in said first position and while said first portion ofsaid elongated wire is continuously rotated in said tube means turningdown another portion of said bar stock to said selected diameter toprovide a second portion of said elongated wire having said selecteddiameter.
 2. The method of claim 1 wherein the inside diameter of saidtube means is less than the diameter of said bead and greater than thediameter of said first portion of said elongated wire and wherein aftersaid bead has been formed in said bar stock and after said first portionis fed into said tube means and advanced to a point where said bead isadjacent said tube means, advancing said tube means at substantially thesame rate as the advancement rate of said bar stock past said cuttingtool.
 3. The method of claim 1 wherein said tube means is held in astationary position; wherein the inside diameter of said tube means isslightly greater than the diameter of said bead means; and wherein aftersaid bead has been formed in said bar stock and after said first portionis fed into said tube means, continuing to advance said first portionand said bead therewith into said tube means.
 4. The method of claim 3wherein after forming portions of said second portion of said wire,advancing said second portion of said wire into said tube means.
 5. Themethod of claim 1 wherein guide bushing means holds said bar stock at aplace adjacent and upstream of said cutting tool rigidly againstmovement out of the line of travel of said bar stock.
 6. A method forforming a beaded transfixion wire for orthopedic uses comprising thesteps of:(a) feeding solid bar stock from a tube feeder into a slidinghead stock means where the bar stock is continuously rotated andadvanced longitudinally along a line of travel; (b) after leaving saidsliding head stock means, feeding the rotating and advancing bar stockpast a cutting tool fixed in a first position to turn down a portion ofsaid bar stock to a selected diameter to provide a first portion of anelongated wire having said selected diameter; (c) holding said bar stockby guide bushing means at a place adjacent and upstream of said cuttingtool rigidly against movement out of the line of travel of said barstock; (d) feeding said first portion of said elongated wiresubstantially completely into tube means for stabilizing said firstportion against any whipping motion; (e) continuing to rotatably feedsaid solid bar stock past said cutting tool while at the same timeprofiling a bead from said solid bar stock by moving said cutting tooloutwardly and inwardly relative to the direction of travel of said barstock; and (f) after said bead has been formed in said bar stock andwith said cuttin tool positioned in said first position turning downanother portion of said bar stock to said selected diameter to provide asecond portion of said elongated wire having said selected diameter andwith the combined lengths of said first and second portions of saidelongated wire having a length to diameter ratio of at least as large as100 to
 1. 7. The method of claim 6 wherein after said second portion hasbeen formed, detaching said second portion from said bar stock bycutting the material with said cutting tool.
 8. The method of claim 7which includes, after the detachment of said second portion, the step ofproviding a drill point on one end of said beaded transfixion wire.